debian man page for sdl::cookbook::opengl

pods::SDL::Cookbook::OpenGL(3pm)			User Contributed Perl Documentation			  pods::SDL::Cookbook::OpenGL(3pm)

NAME
       SDL::Cookbook::OpenGL - Using SDL with OpenGL

CATEGORY
       Cookbook

DESCRIPTION
       As of release 2.5 SDL no longer maintains it's own bindings of OpenGL. Support for OpenGL has been moved over to a more mature
       implementation.

       This implementation is the POGL project. OpenGL is faster and more complete; and works with SDL seamlessly.

   EXAMPLE
       Expanded from Floyd-ATC's OpenGL example.

	       use strict;
	       use warnings;
	       use SDL;
	       use SDLx::App;
	       use SDL::Mouse;
	       use SDL::Video;
	       use SDL::Events;
	       use SDL::Event;
	       use OpenGL qw(:all);

       You can use OpenGL as needed here.

	       my ($SDLAPP, $WIDTH, $HEIGHT, $SDLEVENT);

	       $| = 1;
	       $WIDTH = 1024;
	       $HEIGHT = 768;
	       $SDLAPP = SDLx::App->new(title => "OpenGL App", width => $WIDTH, height => $HEIGHT, gl => 1);
	       $SDLEVENT = SDL::Event->new;

       SDLx::App can start an OpenGL application with the parameter gl => 1.

	       glEnable(GL_DEPTH_TEST);
	       glMatrixMode(GL_PROJECTION);
	       glLoadIdentity;
	       gluPerspective(60, $WIDTH / $HEIGHT, 1, 1000);
	       glTranslatef(0, 0, -20);

       Above we enable GL and set the correct perspective

	       while(1) {
		 &handlepolls;
		 glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
		 glRotatef(.1, 1, 1, 1);
		 &drawscene;
		 $SDLAPP->sync;
	       }

       For SDLx::App sync handles the GL buffer clean.

	       sub drawscene {
		 my ($color, $x, $y, $z);

		 for (-2 .. 2) {
		   glPushMatrix;
		   glTranslatef($_ * 3, 0, 0);
		   glColor3d(1, 0, 0);
		   &draw_cube;
		   glPopMatrix;
		 }

		 return "";
	       }

	       sub draw_cube {
		 my (@indices, @vertices, $face, $vertex, $index, $coords);

		 @indices = qw(4 5 6 7	 1 2 6 5   0 1 5 4
			       0 3 2 1	 0 4 7 3   2 3 7 6);
		 @vertices = ([-1, -1, -1], [ 1, -1, -1],
			      [ 1,  1, -1], [-1,  1, -1],
			      [-1, -1,	1], [ 1, -1,  1],
			      [ 1,  1,	1], [-1,  1,  1]);

		 glBegin(GL_QUADS);

		 foreach my $face (0..5) {
		   foreach my $vertex (0..3) {
		     $index  = $indices[4 * $face + $vertex];
		     $coords = $vertices[$index];

		     glVertex3d(@$coords);
		   }
		 }

		 glEnd;

		 return "";
	       }

       Below we can use SDL::Events as normal:

	       sub handlepolls {
		 my ($type, $key);

		 SDL::Events::pump_events();

		 while (SDL::Events::poll_event($SDLEVENT)) {
		   $type = $SDLEVENT->type();
		   $key = ($type == 2 or $type == 3) ? $SDLEVENT->key_sym : "";

		   if ($type == 4) { printf("You moved the mouse! x=%s y=%s xrel=%s yrel=%s
", $SDLEVENT->motion_x, $SDLEVENT->motion_y, $SDLEVENT->motion_xrel, $SDLEVENT->motion_yrel) }
		   elsif ($type == 2) { print "You are pressing $key
" }
		   elsif ($type == 3) { print "You released $key
" }
		   elsif ($type == 12) { exit }
		   else { print "TYPE $type UNKNOWN!
" }

		   if ($type == 2) {
		     if ($key eq "q" or $key eq "escape") { exit }
		   }
		 }

		 return "";
	       }

SEE ALSO
       perl SDLx::App OpenGL

AUTHORS
       See "AUTHORS" in SDL.

perl v5.14.2							    2012-05-28					  pods::SDL::Cookbook::OpenGL(3pm)